Cable apparatus for conducting gas and electrical current



United States Patent Inventor Guido A. dal Molin,

Westlake, Ohio Appl. No. 672,794 Filed Oct. 4, 1967 Patented Dec. 1,1970 Assignee Unitec a corporation of Ohio CABLE APPARATUS FORCONDUCTING GAS AND ELECTRICAL CURRENT 6 Claims, 19 Drawing Figs.

U.S. C1. 219/130, 219/74 Int. Cl 823k 9/16 Field 01' Search 219/130,136, 74, 75; 339/1nquired References Cited UNITED STATES PATENTS2,666,832 l/1954 Landis et a1. 219/130 2,952,766 9/1960 Craig et a1.219/130 3,155,811 11/1964 Adamson etaL. 219/130 3,239,647 3/1966 lrniger219/130 3,265,856 8/1966 Cecil 219/130 3,436,522 4/1969 Carkhuffet a1219/130 Primary Examiner-.1. V. Truhe Assistant Examiner-J. G. SmithAttorney-Bosworth, Sessions, Herrstrom and Cain ABSTRACT: Cableapparatus for conducting gas and electricity, and if desired, electrodewire, having at least one end of the cable means for making a quicklydisconnectible connection t0 connectible means such as a gun or the likethat emits electric current, gas, and electrode wire ifdesired.

PATENTED DEC 1 SHEET 1 OF 3 VArA a a G a 8 INVENTOR. Guano A. DAL MouwPATENTED um 1970 SHEET 2 OF 3 5! 27 24 11 25' l8 l7 I6 INVENTOR. QuamoA. BALNQLM E w W m a W MA PATENTEDHECI I970 I 3544;758

SHEET 3 OF 3 INVENTOR. Gumo A. DALMOLIL CABLE APPARATUS FOR CONDUCTINGGAS AND ELECTRICAL CURRENT BACKGROUND OF THE INVENTION This inventionrelates to cable apparatus for conducting gas and electricity, andelectrode wire if desired, and more particularly to such apparatuscomprising a flexible cable adapted to be readily and quickly connectedto and disconnected from connectable means such as a gun for emittinggas, electricity and welding wire if desired, or such as means forfeeding into the cable gas, electrical current, and welding wire ifdesired.

For convenience, the invention will be described with reference togas-shielded consumable electric arc welding, in which use it providesparticular advantages, although it may be advantageously used in cuttingapparatus as well as other types of apparatus embodying flexible cablesfor conducting electricity and gas.

In such welding, there is fed into a welding zone in which the weldingoccurs a consumable wire electrode that is connected to one side of anelectrical welding circuit the other side of which is connected to thework to be welded. It is common practice in such welding to surround thewelding zone with a shielding gas to prevent extraction from the ambientair of contaminants such as oxygen or nitrogen that can have adeleterious effect on the metal being welded. The shielding gas may bean inert gas such as helium or argon, and preferably is continuouslysupplied to form a shield or curtain around the tip of the electrode inthe welding zone.

Apparatus heretofore widely used for such welding has embodied a cablethrough which the wire electrode passes and which conducts the electriccurrent from the current supply to the welding zone. However, in suchapparatus the shielding gas has usually been supplied by a separatehose, usually clipped to such cable and connected at one end to a sourceof gas and the other end to the welding gun. This hose, being separatefrom the cable, often tends to-become entangled with objects in thevicinity of the welding zone and also is often in the way of theoperator and impairs his welding efficiency.

Such widely used welding cable also usually has a portion at one end towhich the welding head or gun is attached, and a different-type portionat the other end to which is attached guide or other means for feedingthe electrode wire into the cable. Moreover, the end of the cable nearthe welding head usually tends to wear most since it is handled by theoperator and is often dragged over the floor or other supporting meansin service. Consequently, when the cable becomes excessively worn at oneend, the usual practice is to cut off the worn end ofthe cable andreattach the severed connecter portion to the new unworn end. This is alaborious and time consuming process and inevitably eventually resultsin a cable that is undesirably short. Furthermore, in such priorapparatus, the welding gun is usually connected to the end of the cableby cumbersome means that requires considerable time to effect a gunchange as is often necessary in welding activities. Furthermore, in suchprior cable apparatus there is no provision for permitting rotation ofthe gun relative to the cable, so welding efficiency is reduced becauseof difficulties in manipulation the gun that is nonrotatably attached tothe relatively stiff cable.

Cable constructions have been proposed to overcome some of suchdifficulties. However, in general such apparatus does not permitrotation of the gun relative to the cable, and lacks other desiredfeatures, or is quite complicated in construction or cannot bedisconnected or reconnected to convertible means with as great ease asis often desirable.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide cable apparatus that eliminates as many of the abovedisadvantages as is desired. Another object is the provision of suchapparatus in which shielding gas, electrical current and, if desired,welding electrode wire are all passed through the same cable. A furtherobject is the provision of a cable having connecter LII means making itpossible quickly and easily to connect and disconnect a gun or otherconnectable means such as a feeder to or from the cable, while providingan electrically conductive and gastight joint between the cable andconnectable means. Another object is the provision of such apparatus inwhich the gun or other connectable means can be rotated relative to thecable. Another object is the provision of such apparatus in which thewelding cable has identical connecter portions at both ends so that bothends of the cable can be disconnected from the welding gun and from thefeeder and the ends of the cable can be interchanged to equalize wear. Afurther object of the invention is to provide improved gun apparatus.Another object is to provide improved feeder means. Another object isthe provision of such apparatus which is durable and can be manufacturedat a reasonable cost.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, and featuresof the invention will become apparent from the following description ofthe preferred embodiment in connection with the accompanying drawings inwhich:

FIG. I is an exterior view to a small scale of apparatus embodying theinvention, showing a welding cable having identical connecter portionsat both ends, one connecter portion being connected to a welding gun andthe other connecter portion being connected to a feeder for feedingelectrode wire and shielding gas into the cable; the apparatus alsoincludes schematically depicted electrode circuit means;

FIG. 2 is a sectional elevation to an enlarged scale, of one end of thecable, showing the construction ofone ofthe identical connecterportions, and also the internal construction of a welding gun connectedto such connecter portion;

FIG. 3 is a section through the cable along line 3 -3 of FIG. 1, but tothe same scale as FIG. 2;

FIG. 4 is a section along line 4 -4 of FIG. 2 and to the same scale;

FIG. Sis a section along line 5 -5 of FIG. 2 and to the same scale;

FIG. 6 is a section to the same scale as FIG. 2 through a connecterportion of the cable that is unconnected to any connectable means;

FIG. 7 is an exterior view of-the portion of the welding gun shown inFIG. 2 that would be connected to the connecter portion of the cable,but in this case showing the gun as unconnected;

FIG. 8 is an isometric view of an insert member that is fixed to theconnected end of the gun;

FIG. 9 is a section through the gun along line 9 -9 of FIG. 2 and to thesame scale;

FIG. 10 is an exterior end elevation of a feeder embodying theinvention, to the same scale as FIGS. 2 and 6;

FIG. 11 is a section of the feeder along line 11 -II of FIG. 10 and tothe same scale, the feeder in this FIG, however, being shown asconnected to the end ofthe cable;

FIG. 12 is a side elevational of an electrical switch that may be usedto control the flow of electrical current to and through the weldingcable and gun of the preceding FIGS.

FIG. 13 is a sectional elevation of the switch along line 12 -12 ofFIG.12;

FIG. I4 is a cross section ofthe cable, generally corresponding to FIG.3, but showing another embodiment of the cable having a different typeof liner means for conducting the welding wire and gas;

FIG. 15 is a section along line 15 15 of FIG. 14;

FIGS. 16a, 16b and are respectively isometric, end, and side views ofthe liner used in the cable I of FIG. FIGS. I4, I5; and FIG. 17 is asection, similar to FIG. 6, through the connecter portion of a cableembodying the lines of FIGS. 14, I5, and 16a, 12, c.

DESCRIPTION OF PREFERRED EMBODIMENTS The apparatus shown in FIG. 1comprises a cable 1 having a central portion 2, identical connecterportions 3 and 3', a welding gun 4 connected to one ofthe portions 3,and feeder 5 connected to the other portion 3'. Electrode wire E is fedthrough the cable by feeder S and exits through the gun 4. Gas issupplied by hose 6 to feeder 5 and is discharged through the gun 4.Feeder Sis connected by wire 7 to one side of electrical energy supplycircuit, discussed later, while the work W is connected by wire 8 to theother side ofthe circuit.

As shown in FIGS. 2, 3, 4 and 5, the cable comprises a hollow flexiblenonmagnetic liner 10 having a passage 11 through which the electrodewire E passes; in this embodiment the liner 10 is formed of helicallywound stainless steel wire. This liner is covered by a flexible sheath12 of one or more layers of electrically conductive material, such ascopper strand 13 that acts as the electrical conductor; in thisembodiment each layer of sheathing strand is wound in a helix of steeppitch, as shown externally in FIG. 6, and each strand is formed of alarge number of spirally wound wires of small diameter for increasedflexibility.

A thick sheath 14 of gas sealing, moisture sealing, flexible, resilient,electrically nonconductive material, such as natural or syntheticrubber, plastic material, or other suitable material surrounds theconductive sheath l2,preferably being molded in place over an innerlayer 15 of paper or sheet plastic that is wrapped on the liner 10, toform a gas and water-tight cover. There is thus a gas and moisture tightpassage through the cable.

Sheath 14 extends throughout the portion 2 of the cable into connecterportions 3 and 3'. An end 16 of sheath 12 conductive material projectsfrom each end of sheath 14 of covering material; and an end 17 ofliner10 projects from each end of the sheath 12.

In each connecter portion 3 and 3' of this embodiment, an adapter member18 surrounds the projecting portion 17 of the liner 10 and has a reartapered portion 19 that fits under the projecting portion 16 oftheconductive sheath 14. Member 18 has central bore 20 fits closely overportion 17 of liner 10 and has at least a portion thereof formed withhelical ridges 21 that engage the helical valleys between the wire turnsof liner 10. Adjacent tapered portion 19 is an externally threadedportion 22 terminating in a shoulder 23 formed by generally cylindricalportion 24 of larger diameter. A nut member 25 threaded on portion 22secures member 18 in place by clamping both the nonconductive sheath 14and the conductive sheath 12 to force projecting portion 16 ofconductive sheath 12 against the exterior of tapered portion 22 ofmember 18 and to force the end portion of nonconductive sheath 14against the expanded end portion 16 of sheath 12. The inner surface ofmember 25 has an inwardly projecting ridge 26 that engages the exteriorof sheath 14 to aid in this.

The end of adapter member 18 has a closed end recess 27 of circularcross section; preferably this recess has major inner cylindricalportion 28 terminating at the bottom of the recess in a radiallyextending circular groove 29, and a minor outer cylindrical portion 30of larger diameter, these portions being separated by a radial inwardlyopen groove 31 of a diameter larger than either portion 28 or 30.

Each connecter portion 3 or 3 is covered with sheathlike handle portion33 that is slipped and secured over members 18 and 25 and the adjacentend portion of the nonconductive sheath 14.

The parts described so far and shown primarily in FIG. 6, are assembledas follows. Assuming that there is first a subassembly comprising linerl0, conductive sheath 12 and nonconductive sheath 14, all terminatingapproximately in the same plane at an end ofthe cable, the nonconductivesheath is first cut back to expose a predetermined portion of theconductive sheath. The conductive sheath is then cut back to expose apredetermined portion 17 of liner 10 that projects beyond the conductivesheath. The nut member 25 is then slipped over the nonconductive sheathat such end of the ca ble. The tapered portion of adapter member 18 isthen engaged with the projecting end 17 of the liner. Member 18 is thenrotated to move it axially inwardly along the liner until its taperedinner end portion is forced in between the liner It) and the sheath 12,this being facilitated by engagement of internal helical ridges 21 ofthe liner with the valleys between the turns of wire forming the liner.Such movement of member 18 is continued until the end of conductivesheath 14 rides up a predetermined distance on the tapered portion 19 ofmember 18 and is further continued until a predetermined tension forceis imposed on liner 10 by the action of member 18 pulling on liner 10and pushing on the sheath 12. Nut member 25 is then moved axially androtated until its internal threads engage the external threads ofportion 22 of member 17 and until it firmly clamps sheath 12 and sheath14 between member 25 and member 18.

This clamping action maintains good electrical contact betweenconductive sheath 14 and adapter member 18 and also makes a gastightjoint between the end portion of sheath 14 and the internal wall of nutmember 25 that prevents escape of gas from the interior ofliner 10 pastthe end portion of sheath 14. The tension that is applied to the liner,surprisingly, causes the liner and hence the cable of which the linerforms a part to become considerably limper and more capable of bending,which is an extremely advantageous feature in use. The handle portion 33may then be put in place. The cable thus far described is shown toadvantage in FIG. 6. and

The gun 4 shown in FIGS. 1,2, 7 and 9, is a preferred type of gunembodying the invention that may be employed in connection with theabove-described cable. The gun makes electrically conductive and gastight engagement with a connecter portion 3 or 3 of the cable, and feedselectrode wire, electrical current, and shielding gas to the weldingzone. This gun comprises a suitably curved body portion 34 such as acircular cross section metal tube, preferably of copper, having a thick,stiff wall. The end of this tube nearest the cable is internallythreaded.

An insert member 35 is screwed into these threads by an externallythreaded end portion 36 that forms a gastight electri cally conductivejoint with the tube. Member 35 also has a generally cylindrical endportion 37 with an end ridge 38, which portion is adapted to fit closelybut rotatably in recess 27 of member 18. As shown in FIGS. 2, 7 and 8,member 35 has a central through passage 40 comprising a passage portion41 extending inwardly from its end portion 36, a somewhat smallerpassage portion 42 extending inwardly from portion 41, a passage portion43 extending inwardly from the free end of end portion 37, and anintermediate portion 44 connecting portions 42 and 43 and of smallerdiameter but large enough to permit passage ofthe electrode wire E whileproviding good electrical contact with such wire. Passage portion 42 istapered at 45 from the larger diameter of passage 43 to the smallerdiameter of passage 44 to facilitate entry and a close fit by the freeend of liner 10 when the gun is connected, such free end being taperedfor the purpose; and to facilitate passage of the free end of theelectrode wire E from the interior liner 10 into the passage 44 onthreading ofwire E from the cable into the gun.

Cylindrical portion 37 of insert member 35 has several radial slots 46,four being shown, between the passage 40 and the exterior of portion 37,these slots extending from the free end of portion 37 to a locationspaced inwardly from the groove 31 in recess 27 after the gun isconnected, and communicating with passage 41. Therefore, gas can flowfrom the exterior of the liner 10 through slots 46 to passage 41 andthence to the interior of the body tube 34 ofthe gun.

The generally cylindrical portion 37 of member 35 has a radial outwardlyopen groove 47 that is located directly opposite the groove 31 whenmember 35 is properly located in the member 18. A snap ring 48,preferably an O-ring of suitable resilient, flexible material, isnormally mounted in the groove 47 as shown in FIGS. 2 and 7. When theportion 37 of the member 35 is pushed into the recess 27 of the member18 on the cable, the ring 48 snaps into groove 31 and acts to aid inlocating the gun axially of the member 18 and to seal the gas, whilepermitting rotation of the gun relative to the member 18 and thecable 1. The larger diametered portion 30 of the recess 27 facilitatesconnecting and disconnecting of the gun and snapping of the ring 48 intoand out of position in the groove 31. The slots 46 and associatedportions of the passage 40 also permit the portions of insert member 35between such slots to act as spring fingers that spring inwardly whenthe insert member 35 is pushed into the recess 27 and that springoutwardly to permit ridge portions 38 to fit into the groove 29 furtherto aid in rotatably locking the member 35 in place in the member 18;similarly, these finger portions are sprung inwardly on withdrawal ofmember 35 from recess 27.

Another external groove 49 is formed in cylindrical portion 37 of themember 35 to hold a snap ring 50, preferably metal, that is locatedagainst the end of the member 18 when the gun is connected. This ringlimits inward movement of the member 35 into the recess 27 and alsoperforms other functions to be described later.

The gun 4 also includes annular members 52 and 53 that are mounted nearthe ends of body 34. Each of is members is formed of suitable electricalinsulating and heat-resistant material having substantial structuralstrength, such as Bakelite. Member 52 is locked against movement towardthe adjacent end of member 4 by snap ring 50; member 53 is lockedagainst movement toward the other end of body 34 by another snap ring 54in groove 55 on body 34. An outer tubular covering and handle member 56,formed of metal or other suitable material having sufficient strengthand curved to conform to body 34, is supported in spaced relation tobody 34 by members 52 and 53, being locked in place by shoulders 57 and58 and rings 50 and 54. Member 56 has means providing extended heattransfer surfaces, such as circumferential protuberances 59 that promotetransfer of heat from the member 56 to permit it to remain comfortablycool. Other heat transfer means may be provided; thus the member 56 maybe longitudinally or radially corrugated of finned for the purpose,either internally or externally or both.

Member 56 also has longitudinally spaced openings 60 near its ends topermit passage of air longitudinally through member 56 by convection toaid in cooling.

At its unconnected end body 34 has a reduced diameter portion 62 havingan external thread, and an internal bore 63 larger in diameter than theopening through body 34. Radial openings 64 extend from the longitudinalopening through the body 34 above the bottom ofthe bore 63.

A metal welding tip 65 formed of heat resistant metal and having axialpassage 66 for the welding wire is mounted by one end in bore 63 and isclamped in place by a sleeve 67 and a clamping nut 68 threaded ontoexternal threaded portion 62. The connected end of the welding tip has afrustoconical recess 69 that receives the end of an electrodewire-conducting tube 71 the other end of which extends into member 35 inspaced relation through passage portion 41 and in close relation insmaller passage portion 42 to the end of such passage in alinement withintermediate passage portion 44. This tube 71 can be formed of anysuitable material, but preferably is formed of a wear and relativelyheat resistant synthetic resin material such as nylon or polysulfone.This tube conducts the electrode wire during initial threading upoperation, and later, from passage portion 44 to the passage 66 of thewelding tip.

Shielding means for the welding tip includes a metal sleeve member 72that is fixed to insulating member 53 by being molded or otherwise beingfastened in place by suitable known means. This sleeve member has aportion that projects beyond the insulating member 53 and has externalthreads. Another sleeve member 73, formed of electrical insulatingmaterial of substantial structural strength and heat resistantproperties, at one end bears against the snap ring 54 and at its otherend bears against a shoulder 74 formed in an external sleeve 75 that hasan external lip 76 that engages a clamping nut 77 threaded onto theexternal threads of sleeve 72. Sleeves 72 and 75 are formed ofheat-resistant material such as stainless steel. The metal parts of theshielding means, such as external shielding sleeve 75, are thus firmlysupported from the insulating member 53 without electrical contact withmetal body 34 or any other part including electrical current, Thewelding tip 65 can be readily removed by removing clamping nut 77 topermit removal of sleeves 75 and 73, and by removing clamping nut 68that holds the welding tip in place. A replacement welding tip can bereadily installed by a simple reverse procedure.

Desired gas flow outside of the welding tip to the welding zone at thefree end ofthe welding tip occurs by passage of gas from passage portion41, through the hollow interior of body 34, out through radial passages64, and inside of sleeves 73 and 75 to the desired location.

The feeder 5 attached to cable 1, shown in detail in FIGS. 10 and 11,comprises a body 81 that has fixed to it a supporting bracket 82. Body81 includes a generally cylindrical portion 83 having at its end aradial ridge 84 and radial slots 85 that extend inwardly from the freeend of portion 83 and inwardly from the circular surface to a centralpassage 86. Central passage 86 at the outer end of portion 83 isenlarged at 87 to receive a felt washer 88 that is suitably slottedcentrally at 89 to engage the projecting end of liner 10 at cable 1 andto wipe the passing electrode wire to clean it.

A conduit 91 communicates with passage 86 and supplies gas that passesradially through slots 85 and thence to the interior of liner 10.Passage 86 also is constricted at 92 to aid in supporting a tube 93 ornylon or the like that carries the electrode wire; this tube is lockedin place by set screws 94. Body 81 also has an external groove 95carrying an O-ring 96 that snaps into slot 31 of the adapter member 18of the cable as shown in FIG. 11 to aid in holding the feeder in theproper position in the recess 27 of member 18. The feeder is also heldin place by engagement ofgroove 29 by the ridged portions 84 on the endsof the fingerlike portions of the feeder between the slots 85, and bybearing of bracket portion 82 against the end of cable member 18. Thefeeder thus makes excellent electrical contact with the member 18 whenit is clamped in electrical contact with the conductor sheath 12.

The feeder is adapted to have threaded into its opposite end a member97, which forms part ofa known apparatus for guiding and driving theelectrode wire E through the cable and gun.

Among the advantages ofthe apparatus so far described are the following.Complete relative rotational movement is permitted between the cable andthe welding gun 4 and between the cable and the feeder 5, while both thefeeder and the gun are firmly held and prevented from movementlongitudinally relative to the cable. Despite such permitted relativerotational movements, there are gastightjoints and excellent electricalcontacts between the feeder and the conductive sheath through the cableand between the conductive sheath and the conductive portions of the gunto the welding tip of the gun. Each of the welding gun and the feedercan be readily and rapidly disconnected from the cable by a firm pulllongitudinally of the end of the cable; similarly each can bereconnected by a firm push longitudinally of the end of the cable. Thetension on the liner member of the cable makes the cable limper thanwould otherwise be the case; this is advantageous in handling the cableduring operation. The extended heat transfer surfaces on the outermember of the gun, together with the air cooling through the gun providea gun handle portion that is considerably cooler to the touch thanheretofore possible. In the gun disclosed there cannot be an electricalshort between the shielding portions of the nozzle and the welding tipsince all exterior portions of the gun are completely electricallyinsulated from the welding tip and from all other portions of the gunthat conduct electricity. Heat from the shield sleeve at the welding endof the gun cannot be conducted back to the rest of the gun as the sleeveis heat insulated from the remainder of the gun, The only consumableportions of the gun are the welding tip 65 and the sleeve member 75,both of which can be replaced with ease and at low cost. Therefore, muchless of the gun need be replaced than in conventional guns. The gun canbe connected to and disconnected from the cable without reassembling thegun. The connecter portions 3 and 3' of the cable can be readilyassembled without the need of welding, brazing or other complicatedprocedures. If necessary these end portions can be readily removed andreassembled on other cables, or on properly cut ends of the same cable.Other connected means than those disclosed can be used with cablesembodying the invention.

FIGS. 12 and 13 illustrate to the same scale as FIGS. 2 and 3 anelectrical switch for controlling the flow of electric current to thewelding tip. This switch includes a body 100, having a closed crosssection as shown in FIG. 12 adapted to be slid over the connecterportion 3 or 3 of a cable and lodged between two of protuberances 101formed on handle portion 33 for this and for gripping purposes. The bodyalso pivotally supports at 102 a trigger member 103 having a handle 104adapted to be grasped by the fingers of a hand grasping the connectedportion 3 or 3' of a welding cable. The trigger member has perpendicularto handle 104 a lever portion 105 that carries a button 106 ofinsulatingmaterial. This lever portion 105 is biased by a compression spring 107bearing against the body of the switch to move the handle 104 away fromthe cable and also to move lever portion 105 so its button engagesdepressable plunger 108 ofa commercially available electrical circuitbreaker 109 of the on and off type that is fixed to body 100. Thisplunger is biased to move outwardly of the body of the circuit breaker109. When plunger is held inwardly, the circuit is broken; when theplunger extends outwardly the circuit is completed to allow passageofcurrent. Consequently, in the switch assembly illustrated FIGS. 12 and13 spring 107 normally causes the switch assembly to disconnect the flowof current; while when the handle 104 is manually moved toward the bodyof the cable, the switch assembly permits current flow.

As illustrated by the schematic illustration circuit in FIG. 1, closingof the switch assembly permits the flow of current to the motor 112 thatdrives the generator 113 that supplies current to conductors 7 and 8connected to the feeder and the work.

The remaining FlGS. disclose a cable embodying a different liner 115,preferably a flexible nonmetallic liner formed of extruded nylon orsimilar material, that may be used instead of the metal liner of theprevious embodiment. In this embodiment, the liner 115 of which aportion of the liner alone is shown in FIGS. 16a, 16b and 160, has agenerally star-shaped cross section and comprises a central body 116having a longitudinal opening 117 through which welding wire passes andaround which are fixed radially projecting longitudinally extendingflanges 118. This liner is slid into a flexible metal tubing member 119that is surrounded by electrically conductive sheath 12 similar to thatdescribed in the previous embodiment. Electrode wire travels through theopening 117 while the shielding gas travels through the spaces betweenthe flanges 118 of the liner and the inner surface of tubular member119. The adapter member 18 (FIG. 17) is similar to member 18 of theprevious embodiments, that has a smooth walled central opening 21. Theliner 115 may be readily removed by being slid out of the cable from oneend, and readily reinserted or replaced by a liner slid into the cablefrom one end. Removal or replacement might be desirable to install aliner having a different sized central opening fora different sizedelectrode wire, or for other purposes. Liners of other materials andcross-sectional shapes may be used.

It is apparent that various modifications may be made other than thosedisclosed in the illustrated embodiment without departing from thespirit of the invention. It is intended that the patent shall cover, bysuitable expression in the appended claims, whatever features ofpatentable novelty reside in the invention.

lclaim:

l. A system for transmitting gas and electrical current by a cable andthrough a gun, comprising a cable having at an end thereof a recessedmember of electrically conductive metal, said member having a socketrecess having an axis extending generally axially of the cable and openat said end of the cable, and means connected to said recessed memberfor supplying electrical current to said member and for supplying gas tothe interior of said recess, said recess having an interior wall ofcircular cross section extending for a major portion of the length ofsaid recess and forming part of said recessed member; said gun having abody of electrically conductive metal having at one end a projecting endportion of electrically conductive metal with an exterior surface thatfits closely against the interior wall of said socket recess in saidrecessed member of said cable in metal-to-metal contact to provide goodelectrical conductivity while being capable of rotational movementrelative to said interior wall of said recessed member; and means forrestraining said projecting portion against axial movement out of saidrecess comprising a circumferential inwardly open groove located in saidinterior wall of said recess axially inward from the open end of saidrecess and a circumferential externally open groove located in saidprojecting portion of said gun located opposite said groove in saidrecess of said recessed member when said projecting portion is in placein said recessed member of said cable, and a sealing ring received inboth of said grooves to seal against escape of gas between theprojecting portion of said recessed member while permitting relativerotation between said gun and said recessed member.

2. A system for transmitting gas and electrical current by a cable andthrough a gun, comprising a cable having at an end thereof a recessedmember of electrically conductive metal, said member having a socketrecess having an axis extending generally axially of the cable and openat said end of the cable, and means connected to said recessed memberfor supplying electrical current to said recessed member and forsupplying gas to the interior of said recess, said recess having aninterior wall of circular cross section extending for the major portionof the length of said recess and forming part of said recessed member;said gun having a body of electrically conductive metal having at oneend a projecting portion of electrically conductive metal with anexterior surface that fits closely against the interior wall of saidsocket recess in said recessed member of said cable in metal-to-metalcontact to provide good electrical conductivity while being capable ofrotational movement relative to said interior wall of said recessmember; and means for restraining said projecting portion against axialmovement out of said recess and for holding said exterior surface ofsaid projecting portion against the interior wall of said recess in goodelectrical contact while permitting said relative rotational movement,comprising a circumferential inwardly open groove located in saidinterior wall of said recess axially inwardly from the open end of saidrecess; said projecting portion of said gun having a portion that has atleast one slot extending inwardly from the free end of said projectingportion and having an unslotted portion located inwardly of said slottedportion, means on said unslotted portion for receiving a sealing ringadapted to fit in said circumferential inwardly open groove of saidrecessed member, and an opening extending axially through saidprojecting portion through its slotted portion and its unslottedportion, said opening communicating with said slot in said slottedportion to permit passage of gas between said slot and the portion ofthe opening in said unslotted portion of said projecting portion.

3. The apparatus of claim 1 in which said cable has at each of its twoends one of said recessed members, and said two recessed members areessentially identical.

4. The apparatus of claim 3 comprising feeder means for feeding gas andelectrical current to said cable, which feeder means is connected tosaid recessed member at the end of the cable opposite the end at whichis located the recessed member to which said gun is connected.

5. The apparatus of claim 2 in which said cable has at each of its twoends one of said recessed members, and said two recessed members areessentially identical.

cable opposite the end at which is located the recessed member to whichsaid gun is connected.

qgggg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION I Patent No.3, 544, 758 Dated December 1, 1970 Inventor(s) Guido A. dal Molin It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

I In the heading, the name of the Assignee reads "HNITEC"; should read-UNITEC CORPORATION-- Signed and sealed this 23rd day of March 1971.

(SEA Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SGHUYLER, J'R Attesting OfficerCommissioner of Patents

